The railroad industry employs a variety of auto-rack railroad cars for transporting newly-manufactured vehicles such as automobiles, vans and trucks. Auto-rack railroad cars, known in the railroad industry as auto-rack cars, often travel thousands of miles through varying terrain. One typical type of auto-rack car is compartmented, having two or three floors or decks, two sidewalls, a pair of doors at each end, and a roof. Newly manufactured vehicles are loaded into and unloaded from an auto-rack car for transport by a person (sometimes called a “loader”) who drives the vehicles into or out of the auto-rack car.
One problem with auto-rack cars is the potential for damage to newly manufactured vehicles which can occur in the auto-rack car due to the unwanted movement of one or more of the transported vehicles not adequately secured in the auto-rack car. Various restraint or anchoring systems have been developed for securing the vehicles transported in auto-rack cars to prevent movement or shifting of those vehicles during transportation. The loader typically positions these vehicle restraint or anchoring systems.
One known type of restraint system employs a “tie down” restraint using chains connected to steel runners in the support surface of the auto-rack car. A ratchet tool is usually required to secure these chains taut. Certain types of these known systems utilize winch mechanisms and harnesses which must be fitted over the vehicle tires to restrain movement of the vehicle.
To solve the disadvantages of such mechanisms, various vehicle restraint systems for restraining vehicles transported on auto-rack cars have been developed. Examples of various vehicle restraint systems are disclosed in detail in U.S. Pat. Nos. 4,875,813; 5,037,255; 5,106,245; 5,312,213; 5,316,421 and 5,302,063. These vehicle restraint systems include a plurality of wheel chocks each detachably securable to a support surface of the auto-rack car and an over-the-wheel harness or chock strap which secures one of the tires of the vehicle being transported to the support surface of the auto-rack car. To secure each tire of the vehicle being transported, a wheel chock is place in front of the tire, a wheel chock is placed in back of the tire, and the harness or chock strap is attached to both of these wheel chocks and draped over the tire. The harness or chock strap is then tensioned (utilizing a rotatable torque tube of at least one of the wheel chocks) to hold the draped chock strap in taut condition. Accordingly, the over-the-wheel harness or chock strap keeps the wheel of the car from bouncing over the restraint at times when the railway car is subjected to unusually large impacts. These types of vehicle restraint systems have been widely employed in tri-level auto-rack cars to secure vehicles.
More specifically, to tension the chock strap, an end of the chock strap is attached to a tubular steel reeling shaft or torque tube of the wheel chock. A portion of the torque tube contains a pair of diametrically opposed slots sized to receive the chock strap. The chock strap is affixed to the shaft by threading its first free end through both a first of the slots and a second of the slots, wrapping the chock strap halfway around the torque tube, threading the hem back through the first of the slots, and pulling the second free end of the chock strap to secure the folded first end or hem into the interior of the torque tube. Such a configuration provides that when the original equipment manufacturer (“OEM”) chock strap is tensioned, the chock strap will substantially fill the first of the slots of the torque tube and catch onto itself in the interior of the torque tube to remain securely affixed to the torque tube (and thus enable the chock strap to hold down a tire of the vehicle being transported).
Despite their wide employment in the railroad industry, these OEM chock straps often become cut, torn or otherwise worn or damaged and often need to be replaced. However, the replacement chock straps are often of different sizes and different dimensions than the OEM chock straps. Such different sized replacement chock straps do not provide a proper fit in the interior of the torque tube (i.e., they move around the interior of the torque tube or do not adequately fill the first slot of the torque tube when tension is applied to the chock strap) and thus do not remain securely affixed to the torque tube of the wheel chock. More specifically, one such problem occurs if the replacement chock straps are thinner than the OEM chock straps in this case, the thinner replacement chock strap will fill in or utilize less of the space defined by the slots of the torque tube and thus leave additional space for the replacement chock strap to move or wiggle. This situation additionally provides that when the replacement chock strap is threaded through the torque tube, the formed hem of the replacement chock strap is also thinner and does not remain secure in the interior of the torque tube (i.e., the hem is too thin relative to the size of the interior of the torque tube to properly catch onto itself when the chock strap is drawn snug) and thus the chock strap does not remain secure. Another problem occurs if the hem of the replacement chock strap is longer than the hem of the OEM chock strap. In this case, when the hem is threaded through the torque tube, part of the hem extends through the torque tube and the replacement chock strap is unable to wrap onto itself to remain secure.
Such insecure chock straps present many problems for the railroad industry. One such problem is that while the draped and drawn chock strap initially appears to provide adequate restraint to a car loader, as tension is applied to the chock strap, the insecure chock strap becomes undone. Once undone, the tire is free to bounce over the placed wheel chocks and cause damage to the vehicle being transported. Such damage provides an additional cost to the railroad transporting the vehicle. Another such problem is that the car loader has difficulty in tensioning the draped chock strap to an adequate level of tightness (due to the insecure chock strap not catching on itself) to secure the wheel of the vehicle being transported. Such a problem leads to the car loader having to spend additional time to tension the chock strap properly (and the associated labor costs with the additional time) or the car loader not adequately tensioning the chock strap (and the possibility that the vehicle being transported could be damaged).
Accordingly, a need exists to ensure that different chock straps of different dimensions remain securely affixed to the torque tube of a wheel chock.